# US 4,393,329 A · Article of manufacture for projection television system

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- Number: US 4,393,329 A
- Document ID: US4393329A
- Status: Granted
- Kind: A
- Application number: 06/154,197
- Filed: 1980-05-29
- Granted: 1983-07-12
- Earliest claimed: 1980-01-07
- Assignees: Zenith Radio Corporation
- Inventors: Stanley E. Lehnert
- Web page: https://patentgrep.com/patent/US4393329A

## CPC

- H04N 9/28: Arrangements for convergence or focusing
- H01J 29/861: {Vessels or containers characterised by the form or the structure thereof}
- H04N 9/31: Projection devices for colour picture display {, e.g. using electronic spatial light modulators [ESLM]}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

An article of manufacture is disclosed for use in a projection television system. A cathode ray picture tube has a face panel with a rearwardly extending skirt and a window for receiving a cathodoluminescent imaging screen. The tube has a seal land which defines a plane whose normal makes a non-zero acute angle with respect to the axis of said window. The article is for use in a system having a cathode ray picture tube whose projection optical axis is on the axis of a remotely located viewing screen, and at least one displaced axis cathode ray picture tube; that is, a tube whose projection optical axis is displaced from the axis of the viewing screen by a non-zero acute angle.

## Claims

### Claim 1

For use in a projection television system, an article of manufacture comprising a cathode ray picture tube having a face panel with a rearwardly extending skirt and a window for receiving a cathodoluminescent imaging screen, said tube having a seal land which defines a plane whose normal makes a non-zero acute angle with respect to the axis of said window.

### Claim 2 (depends on 1)

The cathode ray tube defined by claim 1 wherein said face panel is circular.

### Claim 3 (depends on 1)

The cathode ray tube defined by claim 1 wherein said face panel is a rectangle.

### Claim 4

For use in a projection television system, an article of manufacture comprising a glass cathode ray picture tube having a face panel with a rearwardly extending skirt and a window for receiving a cathodoluminescent imaging screen, the edge of said skirt defining a plane whose normal makes a non-zero, acute angle with respect to the axis of said screen.

### Claim 5

For use in a projection television system, an article of manufacture comprising a cathode ray picture tube having a face panel with a rearwardly extending skirt and a window for receiving a cathodoluminescent imaging screen, said panel skirt being conjoinable with a funnel by mating along interfacing edges, with the edge of said skirt defining a plane whose normal makes a non-zero acute cant angle with respect to the axis of said window said funnel edge defining a plane whose normal makes a non-zero acute cant angle with respect to the funnel axis, whereby said funnel can be aligned and conjoined with said face panel to define a selected tilt angle with respect to the axis of said window.

### Claim 6 (depends on 5)

The article of manufacture defined by claim 5 wherein the angle defined by said skirt edge is substantially equal to the angle defined by said funnel edge.

### Claim 7 (depends on 5)

The article of manufacture defined by claim 5 wherein each cant angle is approximately equal to one-half of said tilt angle.

### Claim 8

For use in a projection television system, a cathode ray picture tube whose projection optical axis is displaced from the axis of a remotely located viewing screen by a non-zero acute angle A, and with a cathodoluminescent imaging screen whose axis is substantially coincident with said projection optical axis and normally coincident with the electron-optical axis of said tube, said imaging screen providing an electron-formed visible image for projection on said viewing screen, said cathode ray picture tube having a conjoinable face panel with a rearwardly extending skirt and a funnel which mate along interfacing seal edges, said funnel seal edge being formed to define a plane whose normal makes an angle with respect to the funnel axis substantially equal to one-half said angle A, and with said face panel seal edge formed to define a plane whose normal makes an angle with respect to the imaging screen axis substantially equal to one-half said angle A, said funnel being aligned with respect to said face panel to tilt said electron-optical axis with respect to said projection optical axis by an angle B substantially equal to said angle A, such that when said seal edges are conjoined, the value of said angle B and the orientation of said electron-optical axis causes said electron-formed visible image to have an orientation oand non-linear magnification distortion effective to substantially compensate for the off-axis-induced, non-linear magnification distortion of the light image projected thereby on said viewing screen.

### Claim 9 (depends on 8)

The cathode ray tube defined by claim 8 wherein said face panel is circular.

### Claim 10 (depends on 8)

The cathode ray tube defined by claim 8 wherein said face panel is rectangular.